When water can fall from the sky, be put in storage tanks and from there be delivered via your tap clean and drinkable, thanks to ozonation at the point of use, that is clearly a positive development.

But the potential of localised water cleaning goes a lot further. When an area – especially an area with limited drainage or unreliable water supply – is flooded, there’s undrinkable water everywhere. What can you do with it? Boil it? Not if cookers and stoves are out of action. In some parts of the world there may be no electricity in any case and starting a fire may be impossible.

In both cases local inhabitants may be left in the strange position of receiving clean water delivered by waterborne vessels, or trucks or, aircraft, to affected areas.

What do you do? You need a system to make the water drinkable that doesn’t rely on power, doesn’t need a vast infrastructure and is quickly and easily installed. For peace of mind you will also want to have access to sensors that prove to yourself (and everyone else) that the water is safe.

Once upon a time, had you suggested ozonation you would have been laughed at. Bulky, power-hungry systems complex to operate and impossible to store would not have been much use in delivering clean water in flood areas – and would have been too costly to justify in any case.

But the Aqua21 system has brought down cost, size and power use. You can now easily transport a module that can be attached to a hose or tap and make your water safe. You can also deploy our sensors to confirm that the water is drinkable.

An Aqua21 system that is cheap and flexible enough to send to flooded areas and ensure a clean drinking water supply is still a little way off. And we can’t yet claim the production volume that would be needed. But if you calculate the potential economic effects of dealing with illness from dirty water supplies and paying to provide and deliver clean bottled water, it may become less fanciful to spend money on a relatively new water provision concept. The use of ozonation equipment to clean floodwater for drinking may be closer than you think.